Glossary
BIP-21
BIP-21 is the Bitcoin URI scheme that lets a QR code carry an address plus an optional amount, label and message. It is why every Bitcoin wallet interprets a scanned payment code the same way.
The format
bitcoin:bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq?amount=0.001&label=Coffee
| Parameter | Meaning |
|---|---|
amount |
BTC, up to 8 decimals — not satoshis |
label |
Recipient name |
message |
Note to the payer |
lightning |
BOLT-11 invoice, for a unified code |
Two things that catch people out
Units. amount=1 is one whole bitcoin. Entering a satoshi figure here requests an
absurd sum, and the wallet will display it without complaint.
Case. Bech32 addresses (bc1…) are case-insensitive and can be uppercased so the
encoder uses alphanumeric mode — about 30% fewer modules. Legacy base58 addresses are
case-sensitive and cannot.
Related
- EIP-681 — EIP-681 is the Ethereum URI scheme for payment requests. It carries a recipient address, a chain id and a value in wei, and optionally a contract function…
- EMVCo QR code — EMVCo QR is the international standard for payment QR codes, defining a tag-length-value payload used by PIX in Brazil, PromptPay in Thailand, QRIS in…
- Payload — The payload is the actual string encoded in a QR code — the URL, the WIFI: block, the vCard. Everything about a code's size, density and minimum print…